- The distance to the seat of the fire and concerns of adequate air supply in zero visibility conditions
- The amount of clutter in the structure and concerns of entanglement or entrapment in zero visibility conditions
- The amount of fire, heat and heavy smoke present and concerns of rapid fire spread
- Compromise of structural integrity and concerns of roof collapse in zero visibility conditions
The interior assessment officer, in communication and coordination with command, will then decide on taking one of the following courses of action:
- Interior Attack from Initial Point of Entry: In this scenario, the officer feels comfortable with the short distance to the fire. The relatively clear path to the fire which is free of clutter or entanglement hazards and that the fire is of a manageable size involving only burning contents. (See Figure 1)
- Short Interior Attack from Different Side of Structure, Located Close to Seat of the Fire: In this situation the officer did not like the heavy clutter in the structure and high stacked merchandise with very narrow aisles. The distance to the seat of the fire was also too great to be able to safely advance to the rear of the structure, effectively attack the fire and still have enough breathing air to reach the safety of the exterior at the original point of entry. In this effort, forcible entry of adjacent existing enclosed windows or doors or exterior to interior wall breaching may be conducted to establish a safer means of access close to the seat of the fire. In other words, if safe, firefighters will make their own door when needed. (See Figure 2 and Figure 3)
- Defensive Attack: An immediate withdrawal and initiation of a defensive attack is made. (See Figure 4)
In this scenario, the officer equipped with a thermal imager and accompanied by the crew, has observed a deteriorating condition which can not be safely managed, such as:
- A major portion of the structure is well involved
- The roof which may be constructed of trusses is significantly involved
- The fire involves a large amount of contents in which multiple handlines could not control.
During the interior assessment the assessing officer will keep the distance advanced to a safe minimum. Safety, sector and command officers should be aware that the weight and friction involved in advancing a charged handline will inherently serve to maintain a safe minimum distance by preventing the crew from easily moving forward at a given point without the assistance of the back up companies.
In addition, the officer will withdraw in those instances when the seat of the fire cannot be located. In this case and when dealing with larger enclosed structures, such as those measuring 300 feet by 300 feet or greater in size, a second or third assessment from different points of entry may be conducted. However, depending on the amount of time elapsed and other factors, command may prefer to wait for the fire to flashover or to break through for use of a defensive attack.
Special thanks to: The National Fire Data Center; U.S. Fire Administration and The National Institute for Occupational Safety and Health Firefighter Fatality Investigation and Prevention Program
- Strategy and Tactics for Large Enclosed Structures - Part 1
- Strategy and Tactics for Large Enclosed Structures - Part 2
- Enclosed Structure Disorientation
- Enclosed Structure Standard Operating Guideline (SOG)
- U.S. Fire Adminstration Firefighter Fatalities Homepage
- United States Firefighter Disorientation Study 1979-2001
William R. Mora has dedicated 32 years to the San Antonio, TX, Fire Department as a firefighter, engineer, paramedic and training officer. Captain Mora is currently assigned to the firefighting division. He serves on technical advisory boards for the University of Kentucky, Lexington and has studied educational methodology and hazardous materials in depth at the National Fire Academy.
Captain William Mora is a fire consultant with an interest in firefighter safety, strategy and tactics, standard operating guideline development and firefighter disorientation. Captain Mora has advanced new firefighting terminology, tactics and concepts to help firefighters recognize, manage and avoid the risk at structure fires. He has been published on the topic of firefighter disorientation and enclosed structure tactics in Firehouse.com, Fire Chief Magazine, and Fire Engineering Magazine, as well as in the National Fallen Firefighters Foundation Everyone Goes Home Newsletter. He has given presentations on the prevention of firefighter disorientation for the Fire Department Instructors' Conference, Texas Volunteer Fire Departments and for the Maryland State Firemen's Association.